1. Field of the Invention
The present invention relates to an accommodation block which accommodates electrical connectors for connection with electrical components such as wire harnesses, electrical and electronic circuits, electrical and electronic component parts and the like and which in use is mounted in an electrical connection box. The invention further relates to the electrical connection box, including the accommodation block mounted in it, and more particularly to an electrical connection box for a vehicle such as an automobile.
2. Description of the Related Art
Various electrical and electronic circuits, electrical and electronic component parts, and the like are installed inside a vehicle. An electrical connection box is used to accommodate these electrical and electronic component parts and as a connection branch point for wires such as wire harnesses.
Generally, in an electrical connection box, in order to facilitate assembly and safe storage, connectors of various electrical and electronic component parts and wire harnesses and the like are accommodated inside respective accommodation blocks, depending on kind or function. The accommodation blocks are themselves mounted in the electrical connection box at predetermined respective positions.
A conventional electrical connection box of this type will be described below with reference to FIGS. 10 and 11. This box is similar to that shown in Japanese Utility Model Unexamined Publication No. 63-194053. In this box and according to an embodiment of the present invention described later, the electrical connection box is described with a relay block as the accommodation block, but the same principle is applicable to other accommodation blocks.
As shown in FIGS. 10 and 11, a relay accommodation block 52 is accommodated inside a lower case 51 constituting an electrical connection box 50. The block 52 comprises a block body 53 formed in the shape of an approximately rectangular hollow body. A relay 55 is installed on each of four relay housings 54 formed in an upper portion of the block body 53.
In the vicinity of each lengthwise end of each side wall 56 of the block body 53, an insertion guide 57 is formed extending downward from its upper end portion which is connected with the upper edge of the side wall 56. Each insertion guide 57 has a shape approximately of an inverted "L" from a side view and rectangular from a front view. The lower end of each insertion guide 57 is level with the lower end of the block body 53. A gap C1 is formed between the back surface of each insertion guide 57 and the side wall 56. A reinforcing rib 58 connecting the insertion guide 57 and the side wall 56 with each other is formed vertically in the gap C1.
On each of the side walls 56, a pair of substantially V-shaped locking pieces 59 are formed adjacent insertion guides 57. Each of the locking pieces 59 comprises a base portion 59a fixed to the side wall 56 and a flexible portion 59b deformable toward the base portion 59a. A locking projection or nose 59c projecting toward the insertion guide 57 is formed in the vicinity of the upper end of the flexible portion 59b.
The lower case 51 is box-shaped and its upper part is open, thus having side walls 60a and 60b opposed to each other. Two engaging portions 61 are formed on the inner surface of each of the side walls 60a and 60b. Each engaging portion 61 is formed at a position corresponding to the position of each insertion guide 57 of the relay accommodation block 52. Recess portions 62 into which the insertion guides 57 can be inserted downwardly are formed in the engaging portions 61. A projecting nose 64 is formed on the upper end of a wall 63 of one engaging portion 61 and on the upper end of a wall 63 of the adjacent engaging portion 61. Each nose 64 is formed at a position corresponding to the position of the locking nose 59c of each locking piece 59 of the relay block 52.
An operator assembles the block 52 having the above-described construction inside the lower case 51. The operator inserts the block 52 into the lower case 51 downwardly by holding the relay housing 54 of the relays 55 or the side wall 56 of the relay block 52. At this time, the operator inserts each insertion guide 57 into the corresponding recess portion 62 of each engaging portion 61. This can be done with visual observation by the operator, thus locating the block 52 in position. As the operator inserts each insertion guide 57 further into the corresponding recess portion 62, the flexible portion 59b of each locking piece 59 is pressed by the nose 64 of each engaging portion 61 and thus deformed toward the base portion 59a. Then, simultaneously with contact between the lower surface 57a of the fixed upper end portion of each insertion guide 57 and the upper surface of the corresponding engaging portion 61, each of the deformed flexible portions 59b is released by the respective nose 64. Consequently, the locking nose 59c formed at the upper end of the flexible portion 59b engages under the nose 64. In this manner, the operator positions the relay block 52 in a locked position inside the lower case 51, thus completing the assembly operation.
However, during construction of the conventional block 52 and lower case 51, when the operator inserts each insertion guide 57 into the corresponding recess portion 62 of the engaging portion 61, the position of the operator's hands, which hold the relay block 52 and the block body 53, make it difficult for the operator to easily view all the insertion guides 57. Therefore, the operator has the task of inserting each of the insertion guides 57 into the corresponding recess portion 62 which becomes complicated. Thus, installing the relay block 52 to the lower case 51 is troublesome, and there is a risk of mis-fitting.